Addresses provide the ability to segregate funds within an account.

Every account has a DEFAULT address; that is the address to which postings are normally sent. For a simple current account this address may be the only address in use.

Using extra addresses in an account enables Vault to support use-cases such as:

Rounding up each payment to the nearest whole currency unit and paying this into a savings pot.

To support this use-case, a SAVINGS address is used to collect the round-up amounts.

Ensuring that the FEES applied to an account are treated differently when calculating interest. (For example, where required by regulation.)

To support this use-case, a FEES address is used to hold any fees, separate from the DEFAULT address.